Pressure stabilizing mechanism for feed and draft rolls



Aug. 24, 1937. w. B. HODGE ET AL 2,091,230

PRESSURE STABILIZING MECHANISM FOR FEED AND DRAFT ROLLS Filed July 7, 1934 2 Sheets-Sheet 1 30 1 lnvenTors. l 34 William BHQdge Alber'f W. Thompson ATTys.

A118. '1937- w. B. HODGE ET AL 7 2,091,230

PRESSURE STABILIZING MECHANISM FOR FEED AND DRAFT ROLLS Filed July 7', 1934 2 Sheets-Sheet 2 lnverfiors WiHiom B. Hodge A\berT W.Thompson byWMd W Patented Aug. 24, 1937 UNITED STATES PATENT omen:

PRESSURE STABILIZING MECHANISM FOR FEED AND DRAFjT ROLLS Application July 7, 1934, Serial No. 734,168

, 8 Claims.

This invention relates to improvements in pressure applying and stabilizing mechanism for the drafting mechanism of textile machines of the general type used for drawing out and delivering continuous strands of textile fibres, in the form of roving, sliver, or yarn.

In machines of this general class the material travels between the cooperating surfaces of one or more pairs of rolls, or their equivalent, one

10 roll of each pair being usually fluted and positively driven, and the other, usually the upper roll, covered with a resilient material, such as leather or cork, and subjected to sufficient pressure to cause the material to be grasped by the rolls and positively and continuously delivered thereby.

The saddles are usually mounted upon the rolls and pressure applied through the saddles to the rolls by means of a link, known as a stirrup, which is suspended on an adjustably positioned seat on the saddle and depends therefrom between adjacent pairs of top rolls and lower draft rolls, the lower end of the stirrup being connected to lever mechanism or a spring for applying tension to the stirrup to producethe desired pressure.

The lever mechanism which is commonly used for this purpose comprises a lever of the third class which is connected to the lower eye of the stirrup, the longer arm of the lever having the weight adjustably mounted thereon, and the shorter arm of the lever anchored by an eye bolt to a girder extending lengthwise of the machine, known as the'roller beam, upon which the roll stands, in which the lower rolls are journaled,

are mounted.

In top roll weighting mechanisms of the various types in general use, the saddles by which the pressureis applied to the rolls are subject to alternate elevation and depression due to such causes 40 as variations in the bulk of the material passing through the rolls and eccentricity or peripheral irregularity in either the fluted rolls or the top rolls. The weighted lever, which is characteristic of the usual-mechanism therefore is subject to angular movement in response to such saddle movements and the weight carried by the lever is accordingly. subject to corresponding vertical movement. When the saddle and lever are elevated, the inertia of the weight causes a momentary increase in the tension on the stirrup, but when the upward movement of the saddle ceases, the inertia acquired by the weight during its upward motion causes a momentary reduction in tension and pressure. When the saddle moves downward, the energy of the falling weight causes another momentary and sudden increase in tension upon the stirrup and pressure on the saddle when the downward movement ceases that forcibly compresses the resilient covering on the top rolls and; causes the weight to recoil, resulting in anothermomentary decrease in stirrup tension and saddle pressure.

In the case of high speed textile machinery, such as cotton spinning frames, these characteristic saddle movements alternate so rapidly that the resiliency of the top roll covering causes the entire weighting mechanism to be subjected to vibratory motionor chattering which is necessarily accompanied by corresponding rapidly varying and violent fluctuations in the value of the pressure effective upon the rolls. It is therefore necessary in all such mechanisms because of these wide variations in pressure to use a relatively excessive weight in order that the effective pressure shall never fall below that minimum value at which effective drafting of the material becomes impossible, and it therefore follows that the mean value of the effective pressure is necessarily much higher than that value which would be required for good processing. if the effective pressure ,wereuniform or substantially so, instead of fluctuating between opposite extremes.

Moreover the characteristic vibration and corresponding fiuctuations in saddle pressure above described are the cause of uneven drafting of the material and of corresponding variationsin the thickness of the yarn produced. These variations in thickness impair the breaking strength of the yarn which causes frequent breaks in the strand with consequent interruption to production, waste of material, an increase in the burden and cost ofcattendance, and an increase in the frequency of imperfections due to the .piecing up of broken strands. These characteristic variations in pressure and chattering also are the cause of rapid deterioration of the covering on the top rolls and a corresponding expense for their necessary renewal.

The above defects in the mechanisms com monly used have been largely overcome by pressure stabilizing mechanism for feed and draft rolls for textile machines forming the subject matter of the co-pending application of William H. Sanders, Serial Number 694,181, filed October 18, 1933, which comprises a device for applying elastic pressure to the top rolls of a textile machine and for preventing vibratory movement thereof, comprising a cylinder having a closed lower end and so mounted upon the roll stand that the axis of the cylinder is in alinement with the stirrup. The piston, which is reciprocably mounted in the cylinder, is provided with a piston rod which extends through an apertured head in the cylinder and is connected to the eye of the stirrup. A spiral spring is interposed between the piston and the apertured head of the cylinder and a body of viscous fluid fills the lower portion of the cylinder to and above the piston and acts to retard axial movement thereof in both directions.

By virtue of this construction the spring which acts upon the piston provides the desired elastic pressure upon the top rolls, while the fluid in the cylinder acts to retard the movements of the piston in both directions, and consequently to dampen the vibration of the top rolls while maintaining a substantially uniform stabilized pressure of the rolls upon the material.

The present invention comprises certain. improvements upon the construction. disclosed in the Sanders application.

As heretofore applied in practice, the principle of the Sanders invention has resulted in production of yarns of more even size and Weight and improved strength by virtue of the stabilized pressure characteristic of the Sanders principle. It has also proved possible to materially reduce the pressure effective upon the draft rolls, but it is important that all of the machine units engaged in producing yarn of a particular specification should be uniformly subject to the most desirable value of effective pressure. It is therefore desirable that a pressure-applying device of the type described should include.

(a) Means by which the device may be conveniently attached to existing machinery as a substitute for the usual type of weighting mechanism.

(17) Means for so adjusting the pressure applied to the respective top rolls that uniform pressure thereon may be maintained throughout the machine.

(0) Means for measurably or visibly determining the pressure effective upon the top rolls to facilitate uniform and reasonably accurate adjustment of the effective pressure.

It is the general object of the present invention to provide a pressure applying device of the type described characterized by the above means and also by means for conveniently and inexpensively attaching the device to existing machines as a substitute for the usual type of draft roll weighting mechanism.

In pressure applying devices having the hydraulic stabilizing feature of the type described, the aperture in the head of the liquid-containing cylinder must necessarily be of sufficient size to provide clearance for free movement of the piston rod and when the pressure-applying means is detached from its operative position. there is a likelihood of loss of the fluid contained in the cylinder through the apertured head. Another object of the present invention is the provision of means for preventing such escape of fluid when r the device is not in normal operating position.

Other objects of the invention are:

Provision of adjustable means for connecting the pressure-applying means in operative condition between the roller beam and the stirrup in axial and self-alining retention with the stirrup.

Provision of special means for indicating and conveniently measuring or observing the value of the effective pressure produced by the device when in operation.

Provision of means for preventing strain or injury of the spring used in. the device through excessive compression.

Provision of means for confining the range within which the elastic pressure produced by the device may be adjusted within predetermined maximum and minimum limits to meet the requirements of its use in specified conditions.

Provision of a gauge for conveniently determining the effective pressure produced by the device when employed upon a spinning or similar machine and for facilitating the adjustment of all of the weighting mechanisms on the machinery to an effective pressure of uniform value throughout.

These and other objects and features of the invention will more fully appear from the following description and the accompanying drawings and will be particularly pointed out in the claims.

In the drawings:

Fig. 1 is a side elevation of a pressure applying and stabilizing device shown in assembled position for applying pressure to the top rolls of a textile machine, the journals of the rolls and the roller beam being shown in section;

Fig. 2 is a vertical sectional view through a preferred form of device for applying and stabilizing the pressure applied to the drafting mechanism;

Fig. 3 is a horizontal sectional view on line 3-3 Fig. 2, showing the adjustable connection between the cylinder containing the pressure applying means and the means for adjustabiy securing it to the roller beam;

Fig. 4 is a view similar to Fig. 1, showing a modified construction particularly with reference to the manner in which the pressure applying and stabilizing device is adjustably connected to the roller beam;

Fig. 5 is a detail view illustrating a preferred form of gauge inserted between the head of the cylinder and an enlargement or collar upon the piston rod for the purpose of determining the adjustment of the spring to produce a predetermined pressure upon the top rolls and thereby to enable all of the pressure applying and stabilizing devices on a machine or machines to be set uniformly; and,

Fig. 6 is a sectional view of the gauge shown in Fig. 5 on lines 6-6 Fig. 5, viewed from left to right.

Preferred illustrative embodiments of the invention are shown in the drawings as applied to usual drafting mechanisms in which pressure is applied to the top rolls by weighted levers as above described, or by springs interposed between the saddle stirrup and the roller beam.

In the construction disclosed in Fig. 1 the roller beam l, which forms a part of the frame and extends from end to end thereof, has mounted upon it a plurality of stands (not shown) in the upper end of which the journals of the lower fluted draft rolls 2, 3, and 4, are mounted. The top draft rolls 5, B, and l, are yieldably mounted in suitable bearings and disposed in cooperative relation to the lower rolls 2, 3, and 4. The top rolls 5, 6. and i, are covered with a resilient material, such as leather or cork, and are subjected to sulficient pressure to cause the material passing be-- tween them to be grasped by the rolls with suffi-- cient firmness to insure positive and cont nuous delivery of the material. The lower draft rolls are positively driven at such relative speeds as to produce the desired drawing operation.

Pressure is applied to the top rolls through a saddle comprising an upper equalizing lever B and a lower equalizing lever 9, the lever B engaging the journal of the front feed roll '5 and a suitable projection upon the lower equalizing lever 9 through which pressure is supplied to the rear top rolls 6 and I. The upper equalizing lever 8 of the saddle is provided with an upwardly extending boss It in which is seated an adjustable screw I I having a slotted head I2 and a collar "I3 spaced apart from the head I Z'and a stirrup I4 is provided at its upper end with an eye which engages the adjusting screw I I between the head 62 and collar I3. By adjusting this screw, the point of application of the pressure transmitted through the stirrup I4 to the equalizing lever 8 may be adjusted to vary the relative pressure applied to the front top roll 5 and to the rear top rolls and l, and tosuitably position the stirrup.

The present invention relates particularly to a mechanism or device interposed between the lower end of the stirrup and a member secured to the roller beam I which can be readily assembled upon a usual type 'of machine, or other textile machine, and provided with means for accurately adjusting the tension which is applied to the stirrup and consequently the pressure which is applied to the top rolls, together with means by which the pressure so applied may be accurately determined by a suitable gauge and which will be visually indicated to the operator 0 of the machine.

The device preferably comprises also hydraulically operable mechanism which will dampen and stabilize the pressure applied to the top rolls to prevent vibration thereof and also the provision of means for preventing the escape of fluid when the device is not in operative position, as during storage and shipment, or upon detach- .rent from the stirrup or from the roller beam. The device is also so constructed that axial alinement of the means for transmitting pressure to the stirrup and the stirrup itself may be readily secured in assembling the device and in which such axial alinement may be maintained during the operation of the device.

The preferred construction of the pressure applying and stabilizing device which is illustrated in. section in Fig. 2 comprises a cylinder I5, preferably made from a solid bar, and bored longitudinally to provide an upper cylindrical chamber it and a lower cylindrical chamber I! of somewhat smaller diameter provided with a closed bottom H8. The upper end of the cylinder is provided with external screw threads I9 which are engaged by complementary internal screw threads upon the flange 2!! of a cap 2| having a fiat top surface 22 provided with a central aper ture having a downwardly converging wall 23 forming a valve seat.

A piston 24 of slightly smaller diameter than the internal bore of the chamber I! is fixedly mounted upon the shouldered end of a piston rod 25 and is secured thereupon by a nut 26. A coiled spring 2'! is interposed between the piston 24 and the flat inner face of the cap 22. The spring desirably is designed, manufactured, and tempered with es'pecial care and to a predetermined resilience with close tolerances in respect to initial free length and ratio of load to travel, and is required to reach a condition of contact throughout its coils at a specified ultimate safe load that is so far within the limit of elasticity of the material as to prevent the possibility of strain or injury by excessive compression.

The piston rod 25 is provided with means, such as an enlargement or collar 28, located such dis- "ta'ni'ze from the piston 2 4 as to impose a predetermined initial pressure upon the spring when in engagement with the outer face or valve seat 23 in the cap -2'I. Forinstance, in case an operating tension of eight pounds is desired, the spring may be given an initial compression of five pounds by determining the initial position of the piston with respect to the distance between the upper face of the piston and the inner face of the cylinder cap. A spring having a compression rate of three pounds for each 1 sof an inch of compression would therefore require a compression of "1% of an inch over and above its initial compression corresponding to a load of five pounds. Under these conditions when under a compression of eightpounds, the enlargement or collar 28 would be separated from the valve seat 23 the distance of of an inch. For each additional pressure of three pounds applied to the spring,the collar would be separated from its seat an additional of an inch. By suitable adjustment, therefore, any desired pressure upon the saddle may be readily and accurately determined by gauge measurement and can be visually determined with reasonable accuracy.

Any suitable means may be provided for adjustably connecting the pressure applying and stabilizing device to the stirrup and to the roller beam. As illustrated, the upper end of the piston rod 25 is bent into the form of a hook 29 which is adapted to be inserted into and engage a bayonet slot in the lower end of the stirrup I4 thereby providing a jointed connection between the piston rod and the stirrup to permit selfalining relationship therebetween. The lower end portion of the cylindrical member I5 is provided with external screw threads 30 which engage complementary internal screw threads in a cylindrical socket member 3|, preferably bored to a slightly smaller diameter than that of the screw threaded end of the cylindrical member and tapped with threads complementary to the screw threads 39. The wall of the socket member desirably is provided with a vertical slot 32, Fig. 3, which will permit of sufficient expansion to enable the screw threaded end of the cylinder E5 to be screwed into it. The resilience, therefore, of the socket member will maintain firm engagement between the complementary screw threads and prevent any relative end-wise movement between the cylinder and socket member when in any position of adjustment. The socket member desirably is made from an integral steel bar and bored axially and screw threaded as above described. The lower end of the socket member 30 desirably is reduced to form a flat extension 33 which is provided with a transverse bore or aperture adapted to be slipped over and engage the curved end 35 of a plate or adapter 35 which may be secured to the roller beam I by a machine screw or bolt 3'! inserted in the usual tapped bore which receives the machine screw or belt for securing the stand of the usual weighted lever mechanism or tension spring to the roller beam in ordinary constructions, thereby enabling the present device to be readily applied to old machine constructions.

It will be noted that the present device is pivotally connected to the end 35 of the adapter 36 and therefore can be readily assembled upon a usual type of textile machine, such as a; spinning frame, with the piston rod in axial alinement with the stirrup. It will also be noted that such axial alinement will be automatically maintained irrespective of the adjustment of the stirrup by adjustment of the screw H and also during the movement of the saddle.

The cylinder 95 desirably is provided intermediate of its length with a hexagonal or other angular external enlargement 38 adapted to be engaged by a wrench or other suitable tool to enable the cylinder to be rotated in such a manner as to adjust the lower end thereof into or out of the socket member 3% and thereby to vary the operative compression of the spring. In assembling the device, the hook 2Q of the piston 25 is engaged in the slot in the lower end of the stirrup i and the cylinder then pulled downwardly sufliciently to enable the aperture 3 5 in the lower end of the extension 33 of the socket member to be slipped over the curved end 35 of the adapter. The piston rod 25 will thereby be pulled outwardly so that the piston, which bears upon the lower end of the spring 21, will compress the spring from its initial compression an amount which is proportional to the distance between the enlargement or collar 28 and its seat upon the upper face of the cap 22.

Suitable means may be provided for accurately determining the position of adjustment of the cylinder to provide the correct distance between the enlargement or collar and the cap to impose a predetermined desired pressure upon the top rolls. By reason, therefore, of the construction described, ail of the pressure applying and stabilizing devices which are applied to a spinning machine, or other textile machine, may be set to provide equal pressure upon the drafting mechanism and as a consequence uniformity of the F product of all of the drawing mechanisms will be insured.

The lower portion of the cylinder I5 is filled with a preferably viscous fluid to a level above the maximum limit of movement of the piston 24. The reciprocation of the piston is thereby dampened both in its downward and upward movements, the upward movement being resisted by the vacuum created below the piston, the weight of the oil, and the restricted flow of the oil through the narrow space between the piston and the cylinder wall, while the downward movement of the piston is resisted by the fluid therebeneath which is forced gradually through the narrow space between the piston and cylinder, as in dash pot constructions. Such retardation of the movements of the piston in both directions stabilizes the pressure of the rolls upon the material and eliminates vibration and hammering action, thereby avoiding uneven drafting and attendant breakage of the material.

A modified construction for adjusting the pressure upon the top rolls of drawing mechanism embodying the present invention is illustrated in Fig. 4. In this construction the roller beam i, the lower fluted draft rolls 2, 3, and 4, and complementary top rolls 5, 6, and I, having a resilient covering and the saddle members 8 and 9, are the same, together with the boss l0, adjusting screw ii and stirrup i i. In this construction also the cylinder E5, the cap 26, the piston 24, the piston rod with its enlargement or collar 28, to engage the valve seat in the top 22 of the cap, and the spring 2! interposed between the piston 24 and the under face of the cap 2i, may be and preferably are substantially identical with those heretofore described. In this construction, however, the lower end of the cylinder l5 preferably is provided with a flat extension 39 having a transverse aperture ii! therethrough to receive a hook 4! having a screw threaded shank 42 adapted to engage complementary screw threads in the wall of a bore 43 extending angularly through the roller beam I in axial alinement with the stirrup When the device is assembled upon the machine, as illustrated in Fig. 4, adjustment of the pressure applied through the stirrup l4 to the saddle is accomplished by engaging the angular portion 38 of the cylinder with a suitable tool and rotating the same in a proper direction to cause the shank 42 to enter or withdraw from the roller beam l. Such rotation is in this case permitted as in that perviously described by reason of the fact that the cylinder l5 may be freely rotated about the piston 24, while the flattened end portion 39 of the cylinder l5 will cause a like rotation of the hook 4i and its shank 42. Other equivalent constructions suitable for the accomplishment of the same purpose may be used by those skilled in the art within the scope of the present invention.

It has been mentioned that suitable means may be provided for accurately determining the compression of the spring 2'! by reference to the distance between the upper flat face 22 of the cap 2i and the enlargement or collar upon the piston rod. A suitable gauge for accomplishing this purpose, and which may be employed to set all of the pressure-applying devices for the saddles of the spinning machine, or other drawing machine, is illustrated in Figs. 5 and 6. This device comprises a metallic body having an end portion M, of substantially rectangular form, with an integral tapering portion 45 having a vertical slot 46, preferably extending throughout the length of the tapered portion thereof. The rectangular portion 44 has extending lengthwise through it in alinement with the slot 45, and in parallelism to the flat face 41 of the gauge, a rectangular guideway 48 in which a rectangular gauge rod 49 is slidably mounted. The end of the gauge rod is provided with a tapered portion 59 which merges into the flat edge of the gauge rod 49 to form an edge 5!. A set screw 52 having a milled head and a stem screw threaded into the block portion 44 of the gauge is adapted to abut against the gauge and secure it in any desired adjusted position. Accidental removal of the gauge 49 from its guideway may be prevented by a screw 53, preferably inserted at approximately the beginning of the tapered portion 50, and having its end extending upwardly sufficiently to engage the shoulder at the end of the upper wall of the guideway in which the gauge rod 49 is mounted.

In the operation of the device the slotted end portion of the gauge may be introduced between the flat surface 22 of the cap and the enlargement or shoulder 28 on the piston rod when the device is in operative position, as illustrated in Figs. 1 and 4, and the gauge rod 49 inserted until the edge 5i thereof engages the piston rod.

The gauge rod may be calibrated with respect to the particular type of springs employed with graduations it which will indicate when the edge of the gauge is in engagement with the piston rod the number of pounds of compression to which the spring is subject at that particular distance of the collar or enlargement from the flat surface 23 of the cap 2! of the pressure applying and stabilizing device.

By the use, therefore, of this gauge when properly calibrated with respect to the characteristics of the spring suitable adjustment may be made by rotating the cylinder after the pressure applying and stabilizing device has been installed upon the machine to provide any desired pressure upon the top roll and the pressure applying devices for each of the saddles of the machine may be similarly adjusted and set to provide the same pressure upon all of the saddles, so that the product of all of the sets of drawing rolls will be uniform.

By virtue of the present invention therefore accurate adjustment of the desired pressure to be applied to the saddles of the draft roll mechanism can be accurately determined for all as well as one of the saddle mechanisms of a textile machine having drafting mechanism. By reason of the present invention a skilled machine tender '15 or supervisor can quickly determine whether the relative elevation of the collar from the cap of the pressure applying and stabilizing device is adjusted to maintain the desired effective ten-' sion either by the use of a gauge or, after reasonable experience, by visual inspection. Owing to the large number of spindles in operation in the v each of the many devices employed either by accurate gauging or by visual observation and the means above disclosed are therefore especially useful and valuable in that they provide not H only the means for accurate mechanical adjustment by gauging, but also effective means for adjustment and inspection by sight to a degree of accuracy that has been found to be sufficient for the ordinary requirements in factory practice. Where it is desired to relieve the pressure upon the top rolls during the shutting down of the machine and thereby to avoid distortion of the top roll covering, the pressure applying and stabilizing device can be readily detached by applying such downward pressure to the device as will enable its lower apertured end to be unhooked from the mechanism which retains it upon the roller beam, or if desired the device may be entirely removed by unhooking it from the stirrup. In either event any fluid that is present will be retained in the device by the seating of the collar or enlargement upon the valve seat in the upper surface of the cap, so that the device will be in proper condition for usage when assembled upon the machine.

It will be observed therefore that the collar on the piston rod serves the double purpose of preventing the escape of fluid when present in the device and of providing a means for gauging and accurately determining the pressure effective upon the rolls in devices of the general type described irrespective of the presence or absence of fluid.

Having thus described the invention, what is claimed as new, and desired to be secured by Let- 60 ters Patent, is:

1. As an article of manufacture, a device for the direct application of measurable elastic pressure to the saddle and top rolls of drafting mechanism for textile machines through and in selfalinement with the stirrup and saddle thereof, comprising a liquid containing cylinder having an apertured head, a piston in said cylinder having a piston rod extending through said head, a spiral spring having a predetermined free length interposed between said piston and said apertured head, a fixed collar on said piston rod engaging the outer surface of said head at such distance from said piston, when seated on said cylinder head, as will determine the initial com- 75 pression of said spring, means for operatively connecting said piston rod and the stirrup in mutualself-alinement and longitudinally adjustable means forconnecting the lower end of the cylinder to the frame of the machine.

2. As an article of manufacture, a device for applying, measurable elastic pressure through the saddle and stirrup to the top rolls of drafting mechanism of a textile machine comprising a liquid-containing cylinder having a closed bottom and'an upper head having a central aperture with a surrounding valve seat, a piston in said cylinder having a piston rod extending through the aperture in said head, a spiral compression spring interposed between said piston and said apertured head, a rigid collar on said piston rod forming a valve for said valve seat and so positioned as to determine, when seated, the initial compression of said spring, and means operable respectively detachably to connect said cylinder to the frame and said piston rod to said stirrup.

3. As an article of manufacture, a device for applying elastic pressure through the stirrup and saddle to the top rolls of drafting mechanism of textile machines comprising a spring operated piston and piston rod axially disposed in a cylinder containing fluid for retarding the longitudinal motion of said piston in each direction, means for attaching said cylinder to the frame of the machine, means on said piston rod for operatively connecting the device to said saddle stirrup, and a collar on said piston rod, forming a valve, adapted to be held in engagement with the. head of said cylinder by said spring when said piston rod is not operatively connected to said stirrup thereby closing said cylinder against the escape of fluid.

4. As an article of manufacture, a device for applying elastic pressure through the stirrup and saddle to the top rolls of drafting mechanism of textile machines comprising a cylinder having a closed lower end and an apertured head at the opposite end, a piston in said cylinder having a piston rod extending through said aperture and provided at the outer end thereof with means for operative connection to said stirrup, means connected to the closed lower end of said cylinder for attachment to the frame of the machine, a spiral spring disposed within said cylinder for compression between said piston and said apertured head, a body of viscous fluid in said cylinder acting to retard the movement of said piston in each direction, and a collar on the piston rod adapted to be seated on the outer surface of said apertured head by the initial compression of said spring to prevent escape of fluid therefrom when the device is not operatively con nected to said saddle and said frame, and adapted, when operatively connected to said stirrup and said frame, measurably to indicate the pressure effective upon said top rolls by the compression of said spring in accordance with the distance separating said collar from contact with said apertured head.

5. In a textile machine of the character described having a frame, a draft roll mechanism including lower draft rolls, top draft rolls, a saddle and a stirrup, means for applying stabilized pressure to said top rolls through said saddle comprising a cylinder having a closed lower end and an apertured head, a piston in said cylinder having a piston rod extending through said head and slidably and rotatably mounted therein, a compression spring interposed between said piston and said apertured head, a body of viscous fluid fllling the lower portion of said cylinder to above the limit of movement of said piston, a collar on said piston rod engaging the outer surface of said head at such distance from said piston as to determine the initial compression of said spring, means for connecting said piston rod to the stirrup, means pivotally connecting the lower end of said cylinder to the frame of the machine adapted for adjustment of the compression of said spring by rotation of said cylinder while in operative position, in combination operable adjustably to determine the value of the pressure efiective upon said top rolls by the compression of said spring and in accordance with the distance between said collar and said apertured cylinder head visually to indicate the value of said pressure.

6. In. combination with a device for applying measurable elastic pressure through the stirrup and saddle to the top rolls of the drafting mechanism of a textile machine, a cylinder anchored to the machine having an apertured head, a piston in said cylinder having a piston rod extending through said head connected to said stirrup, a compression spring of known characteristics interposed between said piston and said head, a fixed collar on said piston rod engaging the outer surface of said cylinder head at such distance from said piston as to determine the initial compression of said spring, and adapted when raised from said head by its connection to said stirrup visually to indicate the approximate value of the compression of the spring, and to permit the introduction between said collar and said cylinder of a gauge having means for measuring the distance of compression of the spring and for accurately indicating therefrom the value of the pressure applied to the top rolls.

7. In a textile machine of the character described having a frame, lower draft rolls, top

40 draft rolls provided with saddle mechanism and a stirrup mounted thereon, a cylinder having a closed lower end and a centrally apertured upper head, a piston in said cylinder having a piston rod extending through the aperture in said head, and slidably and rotatably mounted therein, a spiral spring of predetermined free length and resilience disposed for axial compression between said piston and said apertured head, a body of fluid filling said cylinder to well above the uppermost position attainable by said piston, whereby the reciprocation of the piston will be dampened both in its downward and upward movements,

means respectively connecting said piston rod to said stirrup and said cylinder to said frame operable to produce axial self-alinement of said cyl inder, piston rod and stirrup when in operative position, and also operable by rotatable adjustment of said cylinder to adjust the initial compression of said spring.

8. In a textile machine of the character described having a frame, lower draft rolls, top draft rolls provided with saddle mechanism and a stirrup mounted thereon, a cylinder having a closed lower end and a centrally apertured upper head, a piston in said cylinder having a piston rod extending through the aperture in said head, and slidably and rotatably mounted therein, a spiral spring disposed for axial compression between said piston and said apertured head, a body of fluid filling said cylinder to above the uppermost position attainable by said piston, means connecting said piston rod to said stirrup, to permit self-alining relationship therebetween, and means for securing said cylinder to said frame comprising a reduced extension of said cylinder provided with an eye and a hook adapted to engage said eye mounted on said frame.

WILLIAM B. HODGE. ALBERT W. THOMPSON. 

